1. Field of the Invention
The present invention relates generally to medical methods and devices for accessing body lumens and in particular to methods and apparatus for identifying ductal orifices in human breasts and accessing the ducts through the identified orifices.
Breast cancer is the most common cancer in women, with well over 100,000 new cases being diagnosed each year. Even greater numbers of women, however, have symptoms associated with breast diseases, both benign and malignant, and must undergo further diagnosis and evaluation in order to determine whether breast cancer exists. To that end, a variety of diagnostic techniques have been developed, the most common of which are surgical techniques including core biopsy and excisional biopsy. Recently, fine needle aspiration (FNA) cytology has been developed which is less invasive than the surgical techniques, but which is not always a substitute for surgical biopsy.
A variety of other diagnostic techniques have been proposed for research purposes. Of particular interest to the present invention, fluids from the breast ducts have been externally collected, analyzed, and correlated to some extent with the risk of breast cancer. Such fluid collection, however, is generally taken from the surface of the nipple and represents fluid from the entire ductal structure or from a single duct which is spontaneously discharging. In either case, information on the condition of a preselected individual duct is generally not provided. Information on individual ducts can be obtained through cannulation and endoscopic examination, but such examinations have been primarily in women with nipple discharge or for research purposes and have generally not provided for examination of each individual duct in the breast.
Since breast cancer usually arises from a single ductal system and exists in a precancerous state for a number A of years, endoscopy in and fluid collection from individual breast ducts holds great diagnostic and therapeutic promise. Much of the promise, however, cannot be realized until identification of and access to each and every duct in a patient""s breast can be assured. Presently, ductal access may be obtained by a magnification of the nipple and identification of ductal orifice(s) using conventional medical magnifiers, such as magnification loupes. While such magnified examination is relatively simple, it cannot be relied on to identify all orifices. Moreover, the ductal orifices can be confused with other tissue structures, such as sebaceous glands and simple keratin-filled caruncles of the nipple. Thus, before ductal techniques can be further developed for diagnosis, therapy, research, or other purposes, it will be useful to provide methods and apparatus which facilitate identification of ductal orifices to distinguish them from other nipple surface features, and allow subsequent ductal access in selected and/or all ducts in each breast.
2. Description of the Background Art
Publications by the inventors herein relating to breast duct access include Love and Barsky (1996) Lancet 348: 997-999; Love (1992) xe2x80x9cBreast duct endoscopy: a pilot study of a potential technique for evaluating intraductal disease,xe2x80x9d presented at 15th Annual San Antonio Breast Cancer Symposium, San Antonio, Tex., Abstract 197; Barsky and Love (1996) xe2x80x9cPathological analysis of breast duct endoscoped mastectomies,xe2x80x9d Laboratory Investigation, Modern Pathology, Abstract 67. A description of the inventors"" breast duct access work was presented in Lewis (1997) Biophotonics International, pages 27-28, May/June 1997.
Nipple aspiration and/or the introduction of contrast medium into breast ducts prior to imaging are described in Sartorius (1995) Breast Cancer Res. Treat. 35: 255-266; Satorious et al. (1977) xe2x80x9cContrast ductography for the recognition and localization of benign and malignant breast lesions: An improved technique,xe2x80x9d in: Logan (ed.), Breast Carcinoma, New York, Wiley, pp. 281-300; Petrakis (1993) Cancer Epidem. Biomarker Prev. 2: 3-10; Petrakis (1993) Epidem. Rev. 15: 188-195; Petrakis (1986) Breast Cancer Res. Treat. 8: 7-19; Wrensch et al. (1992) Am. J. Epidem. 135: 130-141; Wrensch et al. (1990) Breast Cancer Res. Treat. 15: 39-51; and Wrensch et al. (1989) Cancer Res. 49: 2168-2174. The presence of abnormal biomarkers in fine needle breast aspirates is described in Fabian et al. (1993) Proc. Ann. Meet. Am. Assoc. Cancer Res. 34: A1556. The use of a rigid 1.2 mm ductoscope to identify intraductal papillomas in women with nipple discharge is described in Makita et al. (1991) Breast Cancer Res. Treat. 18: 179-188. The use of a 0.4 mm flexible scope to investigate nipple discharge is described in Okazaki et al. (1991) Jpn. J. Clin. Oncol. 21: 188-193. The detection of CEA in fluids obtained by a nipple blot is described in Imayama et al. (1996) Cancer 78: 1229-1234. Delivery of epithelium-destroying agents to breasts by ductal cannulation is described in WO 97/05898.
The present invention provides improved methods, kits, and other apparatus for locating breast ducts in the breasts of human patients. In particular, the methods of the present invention permit reliable identification of the orifices within the nipple of a breast, where individual orifices lead to each of the multiple ductal networks within the breast. By reliably identifying each orifice, all of the ductal networks can be located and subsequently accessed for diagnostic, risk assessment, therapeutic, research, or other purposes.
Broadly, the present includes a wide variety of techniques for transiently marking and locating individual orifices in a nipple of a breast, usually a human breast. By xe2x80x9cmarking,xe2x80x9d it is meant that a substance, label, energy, or stimulus is applied to the nipple to cause labelling, a reaction, or other response which permits or enhances distinguishing an orifice from surrounding tissue in the nipple. Usually, but not necessarily, the methods will result in the marking of all orifices in a nipple to permit subsequent access to all or selected one(s) of the ductal networks associated with the orifices. The marking will be xe2x80x9ctransient,xe2x80x9d e.g. will not be permanent but instead will remain visible or otherwise detectable for a time sufficient to permit subsequent access to the associated ductal lumens, usually for a period of at least 15 minutes, preferably for about 1 to 2 hours. For the most part, the present invention will rely on introducing a detectable substance, such as a labelling reagent, dye, or the like, to the nipple so that the substance localizes and/or accumulates at or near the orifice to permit visual, automated, or other detection. Alternatively, the present invention can utilize other stimuli for inducing a response, change, or reaction at or near a location of the orifice in the nipple. For example, it may be possible to illuminate the nipple with certain light or other energies which help distinguish between the orifice and other tissue surfaces. It may also be possible to introduce chemical reagents which react with ductal secretions at the orifice to enhance visibility e.g. to produce a visible or otherwise detectable reaction product.
In a first aspect of the present invention, a method for locating an orifice of a breast duct comprises labelling ductal cells disposed at the ductal orifice with a visible or otherwise detectable label. The orifice may then be located based on the presence of the label at the orifice. Specific and preferred methods for labeling the orifices are described below in connection with a second aspect of the present invention. After the orifices have been located, an access device, such as a guidewire, catheter or fiberoptic viewing scope, can be introduced through at least one of the orifices and into the associated breast duct. The method may further comprise introducing the same or a different access device through other orifices, often into each of the orifices to permit diagnosis, treatment, or other evaluation of all of the ductal networks of a breast.
An exemplary labelling method includes treating a nipple to expose tissue in an orifice of each duct. The treated nipple is then exposed to a labelling reagent capable of specifically binding to a tissue marker characteristic of tissue at the ductal orifice. Binding of the labelling reagent to the tissue results in immobilization of a label at the orifice, permitting subsequent location of the orifice as described above. The treating step preferably comprises washing the nipple with a keratinolytic agent, such as 5% to 50% acetic acid (by weight), to remove keratin-containing materials which normally occlude the duct orifice and which could inhibit binding of the labelling reagent to the tissue marker. The tissue marker is typically characteristic of the ductal epithelium and represents either a membrane antigen or a cytoplasmic antigen. It has been found by the inventors herein that the ductal epithelium extends to within 0.1 mm to 0.2 mm of the nipple orifice and is sufficiently exposed to the surface of the nipple to permit labelling according to the methods of the present invention. Exemplary markers include cytokeratins, such as cytokeratin 8, cytokeratin 18; cadhedrins, such as E cadhedrin; epithelial membrane antigen (EMA);and the like. Usually, the labelling reagent comprises a polyclonal or monoclonal antibody or other specific binding substance specific for the marker. The antibody may be directly labelled with a visible label, such as a fluorescent label, a dye label, a chemiluminescent label, or the like. Alternatively, the labeling reagent may comprise two or more components, typically including a primary antibody which is specific for the marker and one or more secondary binding substances which bind to the primary antibody and provide a label, optionally a magnified label. For example, the primary antibody may be unlabelled, and a secondary labelled antibody specific for the primary antibody may also be provided. As a further alternative, the primary antibody can be labelled with biotin or other hapten, and binding of the label provided via avidin, secondary antibody specific for the hapten, or the like. Numerous specific techniques for labelling of antigenic tissue markers are well known and reported in the immunocytochemical staining literature.
In an alternative aspect of the present invention, one or more ductal orifices in a nipple are labelled by introducing a dye into the, usually at the base of the nipple. It is presently believed that the dye first collects in the lactiferous sinuses associated with one or more (usually all) of the ductal networks and then travels toward the surface of the nipple via a capillary mechanism through the associated ductal orifice. It is further believed that the dye localizes primarily in the ductal lumens because the cebaceous glands of the nipple do not extend fully to the base. Thus, dyes injected at the base or blow will not pass directly into the cebaceous glands. Regardless of the correctness of this presently believed mechanism, it has been found that introduction of a dye into the base of a nipple results in subsequent accumulation of the dye at at least some of and usually all of the ductal orifices. Dye labelling of all of the ductal orifices can be achieved by introducing a sufficient volume of the dye to the nipple base and/or distributing the dye evenly over the nipple base so that the dye can travel to all of the ductal lumens. Suitable dye volumes are in the range from 0.001 ml to 100 ml, preferably from 0.01 ml to 10 ml, and typically from 0.1 ml to 5 ml. In the exemplary methods, the dyes are injected using a needle and syringe, and uniform distribution of the dye over the nipple base can be enhanced-by moving the needle to slightly different locations. Usually, however, moving of the needle will not be necessary to achieve labelling of all of the ductal orifices. Suitable dyes may be colored, fluorescent, chemiluminescent, vital dyes, or the like. The dyes will be biocompatible, non-toxic, and will preferably be non-aqueous so that they are not adsorbed directly into the tissue, but rather preferentially collect within the sinuses lumens and travel to the ductal orifices. Suitable dyes include Metylene blue, Indigo carmine, Pontamine sky blue 6BX (Chicago sky blue 6B), fluorescein, Toluidine blue 0, Indocyanine green (sodium salt), Rose bengal, Patent blue violet (Patent blue), Isosulfan blue and Rhodamine B.
In another aspect, a method according to the present invention comprises marking a ductal orifice and subsequently accessing the duct through the marked orifice. Marking may comprise any of the specific methods set forth above. Accessing comprises introducing an access device through at least one of the marked orifices, and preferably through all of the marked orifices, where the access device may be a catheter, a guidewire, a fiber optic viewing scope, or the like.
In still another aspect of the present invention, a kit for labelling breast duct orifices comprises a detectable substance, such as a labelling reagent, dye, or reagents capable of specifically labelling a cellular marker at the ductal orifice, instructions setting forth a labelling method as described above, and a package containing the detectable substance and the instructions for use. Optionally, the kits of the present invention may further include the keratinolytic agent (particularly for the specific labelling protocols) and any other reagents that may be helpful or necessary for performing the method. Instructions for use will set forth the use of all provided reagents and may further set forth the use of agents which are available in the laboratory where the assay is to be performed.
In yet another aspect of the present invention, a kit for accessing a breast duct comprises a detectable substance for marking a ductal orifice. The kit further comprises an access device capable of being inserted through a marked ductal orifice to a ductal lumen, such as a catheter, a guidewire, a fiber optic viewing scope, or the like. The kit still further comprises a package containing the labelling reagent, optionally other reagents or components, and the access device. The kit may further comprise instructions for use setting forth a method comprising the accessing steps as described above.